I haven't played BSG, only watched half a game of it, but from the rules explanation alone (there were a few other newcomers to the game at the table), I'd peg SoC as the easier game to teach and pick up. It's pretty straightforward in its mechanics, which makes it a good gateway co-op. If you're looking for something to bring people into the hobby, don't already have a gateway co-op (Pandemic, Forbidden Island), and have the cash to spare, I'd say go for it.